Trunk Cross-sectional Area Research Articles

Integrated fertilization: An approach for higher apple (Malus domestica) productivity and ecological health of soil

A field experiment was conducted to study the effect of organic and inorganic fertilizers supplemented with biofertilizers (Azotobacter and Microphos) on growth parameters of apple (Malus domestica Borkh. cv. Oregon Spur) for three years (2012 to 2014) in Srinagar, Jammu and Kashmir, India. The pooled data of three years revealed that, maximum fruit number (127/plant), fruit weight (113 g), yield/plant (14.5 kg), yield/ha (23.2 tonnes) and production efficiency (117g/cm2 TCSA) were recorded in treatment received 75% of recommended dose of fertilizer (RDF) + 25% N through FYM + Microphos while minimum was recorded in control. The percentage increase in trunk cross section area during the three years of experiment was maximum 17.5% and 16.8% with application of 75% of RDF + 25% N through FYM + Microphos and Azotobacter, respectively, while minimum (8.0%) in control. Among the INM, treatment comprising 75% of RDF + FYM and biofertilizers (either Azotobacter or Microphos) was found significantly superior over rest of the treatments in-terms of improving soil health parameter, viz. dehydrogenase activity, organic carbon, available NPK and DTPA-Zn. Overall, study reveals that, through application of 75% of RDF + FYM and biofertilizers double the productivity of apple, which can gain the momentum of apple production in Kashmir valley of India with quality produce and maximize economic benefits to farmers.

Evaluation of Morpho-Physiological Traits Adjustment of Prosopis tamarugo Under Long-Term Groundwater Depletion in the Hyper-Arid Atacama Desert.

Water extraction from the underground aquifers of the Pampa del Tamarugal (Atacama Desert, Chile) reduced the growing area of Prosopis tamarugo, a strict phreatic species endemic to northern Chile. The objective of this work was to evaluate the effect of various architectural and morpho-physiological traits adjustment of P. tamarugo subjected to three groundwater depletion intervals (GWDr): <1 m (control), 1–4 m and 6–9 m. The traits were evaluated at three levels, plant [height, trunk cross-section area, leaf fraction (fGCC), and crown size], organ [length of internodes, leaf mass per unit area (LMA), leaflet mass and area], and tissue level [wood density (WD), leaf 13C, 18O isotope composition (δ), and intrinsic water use efficiency (iWUE)]. In addition, soil water content (VWC) to 1.3 m soil depth, pre-dawn and midday water potential difference (ΔΨ), and stomatal conductance (gs) were evaluated. At the deeper GWDr, P. tamarugo experienced significant growth restriction and reduced fGCC, the remaining canopy had a significantly higher LMA associated with smaller leaflets. No differences in internode length and WD were observed. Values for δ13C and δ18O indicated that as GWDr increased, iWUE increased as a result of partial stomata closure with no significant effect on net assimilation over time. The morpho-physiological changes experienced by P. tamarugo allowed it to acclimate and survive in a condition of groundwater depletion, keeping a functional but diminished canopy. These adjustments allowed maintenance of a relatively high gs; ΔΨ was not different among GWDrs despite smaller VWC at greater GWDr. Although current conservation initiatives of this species are promising, forest deterioration is expected continue as groundwater depth increases.

Partitioning of Dry Matter into Fruit Explains Cultivar Differences in Vigor in Young Olive (Olea europaea L.) Trees

Low vigor and early and abundant production are desirable traits for modern tree crops. In olive, most cultivars are too vigorous and cannot be successfully constrained in the small volume allowed by the straddle harvester used in the so-called superhigh-density (SHD) orchards. Only few cultivars appear to have sufficiently low vigor to be suitable for this system. These cultivars combine low vigor with earlier and higher yield. This study investigated the hypothesis that differences in vigor between Arbequina, a low vigor and the most commonly used cultivar in SHD orchards, and Frantoio, a highly vigorous cultivar not suitable for such orchards, are related to their differences in early bearing and consequent differences in dry matter partitioning into fruit. Young trees of both cultivars were deflowered either in 2014, 2015, both years, or neither one, resulting in a range of cumulative yields over the 2 years. Tree trunk cross-sectional area (TCSA) was measured at the beginning of each year. This was closely related to total tree mass, as assessed at the beginning and at the end of the experiment. Cumulative yield, in terms of fruit dry matter, was also assessed. TCSA increased less in fruiting trees in both years. As expected, when not deflowered, ‘Frantoio’ was less productive and more vigorous than ‘Arbequina’. However, there was no difference in TCSA increment when both cultivars were completely deflowered. TCSA increments were closely inversely related to yield across all treatments and cultivars (R2 = 0.90). The regressions improved further when data from 2015 only were used (R2 = 0.99). The results represent the first quantitative report showing that differences in vigor among cultivars can be completely explained in terms of different dry matter partitioning into fruit, supporting the hypothesis that early bearing is a major cause, rather than merely a consequence, of lower vigor in young ‘Arbequina’ trees. These results provide new understanding on vigor differences across cultivars, which will be useful for breeding and selection of new genotypes.

Resource investments in reproductive growth proportionately limit investments in whole-tree vegetative growth in young olive trees with varying crop loads

It has long been debated whether tree growth is source limited, or whether photosynthesis is adjusted to the actual sink demand, directly regulated by internal and environmental factors. Many studies support both possibilities, but no studies have provided quantitative data at the whole-tree level, across different cultivars and fruit load treatments. This study investigated the effect of different levels of reproductive growth on whole-tree biomass growth across two olive cultivars with different growth rates (i.e., Arbequina, slow-growing and Frantoio, fast-growing), over 2 years. Young trees of both cultivars were completely deflowered either in 2014, 2015, both years or never, providing a range of levels of cumulated reproductive growth over the 2 years. Total vegetative dry matter growth over the 2 years was assessed by destructive sampling (whole tree). Vegetative growth increased significantly less in fruiting trees, however, the total of vegetative and reproductive growth did not differ significantly for any treatment or cultivar. Vegetative growth over the 2 years was closely (R2 = 0.89) and inversely related to reproductive growth across all treatments and cultivars. When using data from 2015 only, the regression improved further (i.e., R2 = 0.99). When biomass was converted into grams of glucose equivalents, based on the chemical composition of the different parts, the results indicated that for every gram of glucose equivalent invested in reproductive growth, vegetative growth was reduced by 0.73-0.78 g of glucose equivalent. This indicates that competition for resources played a major role in determining tree growth, but also that photosynthesis was probably also enhanced at increasing fruit load (or downregulated at decreasing fruit load). The leaf area per unit of trunk cross sectional area increased with deflowering (i.e., decreased with reproductive growth), suggesting that water relations might have limited photosynthesis in deflowered plants, which had much greater canopies. Net assimilation rate (NAR) increased with reproductive growth and decreased with plant size. Net assimilation rate was also negatively correlated with the leaf area per unit of trunk cross sectional area, suggesting that water relations might have contributed to decreasing NAR at increasing plant size.

Assessment of different irrigation strategies on yield and quality characteristics of drip irrigated pomegranate under mediterranean conditions

This research was carried out to determine the effect of drip irrigation strategies on yield and quality characteristics of pomegranate (Punica granatum L. cv. Hicaznar) trees during the growing seasons between 2013 and 2015 years at Bati Akdeniz Agricultural Research Institute in Antalya, Turkey. The amount of irrigation water applied was based on cumulative Class A pan evaporation (Kcp1 0.50, Kcp2 0.75, Kcp3 1.00 and Kcp4 1.25) measured in two irrigation intervals (D1, 3 days; D2, 6 days). It was determined that irrigation intervals did not affect yield, while irrigation water levels were found to be statistically significant. The average water consumptions determined from a soil water balance were 797 mm for Kcp4, 730 mm for Kcp3, 658 mm for Kcp2, and 591 mm for Kcp1 irrigation level. According to the averaged values of 3 years, annual yield for Kcp4, Kcp3, Kcp2, and Kcp1 irrigation levels were 29.2, 28.9, 23.6, and 18.8 t ha−1, respectively. While the effects of irrigation treatment on fruit weight, total soluble solids, total acidity and pH of juice were not significant, its effect on canopy volume and total trunk cross sectional area were found to be significant. It is concluded that pomegranate trees can be irrigated at 6 days interval using the amount of irrigation equal to 75% of cumulative Class A Pan evaporation to obtain the highest water use efficiency.

‘SUMMIT’ SWEET CHERRY CULTIVAR ON DIFFERENT ROOTSTOCKS

The goal of this study was to examine the effect of seven cherry rootstocks (‘Gisela 5’, ‘Gisela 6’, ‘CAB 6P’, ‘Alkavo 2’, ‘F 12/1’, ‘MaxMa14’ and ‘MaxMa 60’) on the growth and productivity of ‘Summit’ sweet cherry cultivar. The trees were planted in the spring of 2008 at distances of 4.0 x 3.0 m, shaped in freely growing crown and irrigated by spraying over the crowns. Tree vigour (trunk cross-sectional area and crown volume), yield, yield efficiency and fruit quality were recorded each year in the period 2008-2016. The results clearly showed the influence of rootstocks on the trees growth. Nine years after planting the most vigorous rootstock was ‘MaxMa 60’ and the weakest were ‘Gisela 5’ and ‘Gisela 6’. The highest 4-year cumulative yield per tree was obtained with ‘MaxMa 60’, followed by ‘CAB 6P’ and ‘MaxMa 14’. Rootstocks ‘Gisela 5’ and ‘Gisela 6’ negatively influenced yield and fruit size.

PERFORMANCE OF MONDIAL GALA APPLE CULTIVARS GRAFTED ON M9 APPLE ROOTSTOCK IN THE MEDITERRANEAN REGION OF TURKEY

This research was carried out on eight-year-old trees of the Mondial Gala (Malus domestica Borkh) cultivars grafted on the M9 rootstock in order to determine its performance in the Mediterranean region with subtropical climatic conditions in Mersin, Turkey. In the study, flowering times, yield and fruit quality parameters were investigated. Mondial Gala planted with planting spaces of 1x3 m. According to the results, first flowering was observed on April 1, full flowering on April 10 and end of flowering on April 17, and fruits were harvested at the end of July. The fruit weight (average 223.2 g), the yield per tree (average 22.6 kg), and yield per trunk cross-sectional area was observed as 0.56 kg/cm2 at the end of the eighth year. Observed values indicated that Mondial Gala summer apple cultivars were found to be promising for early apple growing in the higher parts of subtropical ecological conditions of Turkey.

Evaluation of agronomic and fruit quality traits of fig tree varieties (Ficus carica L.) grown in Mediterranean conditions

In this work, the agronomic behaviour and fruit quality of ten varieties of common fig were evaluated for the establishment of new commercial orchards destined for fresh consumption. The following traits were measured: annual yield, cumulative yield, trunk cross sectional area (TCSA) and yield efficiency of each variety, as well as weight, width, total soluble solids (TSS), pH, titratable acidity (TA) and maturation index (MI) of brebas and figs. The results show that ‘Banane’ and ‘Brown Turkey’ were the earliest to enter into production, and ‘Banane’ showed the highest annual yield in the 7th green (2014), with 76 kg/tree, followed by ‘Brown Turkey’ (57.6 kg/tree), ‘Cuello Dama Blanco’ (52 kg/tree) and ‘Colar Elche’ (39 kg/tree). On the other hand, 'Cuello Dama Blanco' and 'De Rey' exhibited the better organoleptic traits, with TSS and MI values ranged from 18.7 ºBrix and 203.3 MI (‘Cuello Dama Blanco’) to 20.4 ºBrix and 187.1 MI (‘De Rey’) for brebas and from 21.4 ºBrix and 278.7 (‘Cuello Dama Blanco’) to 23.3 ºBrix and 255.6 (‘De Rey’) for figs. This study will allow the fruit grower to select the most interesting and appropriate range of varieties based on market needs taking into account the ripening season (early, middle or late) and fruit colour (green, purple or black).

Efficacy of Anaerobic Soil Disinfestation for Control of Prunus Replant Disease.

Prunus replant disease (PRD) is an important soilborne complex that suppresses growth and productivity of replanted stone fruit and nut orchards. It is effectively managed with preplant soil fumigation but, due to regulatory challenges, nonfumigant-based control strategies for PRD and other soilborne disease problems may become increasingly important, especially in California. We examined the potential of preplant anaerobic soil disinfestation (ASD) for control of PRD in four repeated orchard replant trials on sandy loam soil near Parlier, CA. After removal of the old orchard trees, alternative ASD treatments, all using rice bran as the main carbon source, were implemented, starting in late September. The alternative treatments incorporated rice bran at (i) 20 t ha-1, alone, in 3.0-m-wide row strips; (ii) 20 t ha-1, preceded by incorporation of a sudangrass cover crop and followed by drip application of molasses (10 t ha-1), in 3.0-m-wide row strips; (iii) 20 t ha-1, alone, in 1.8-m-wide strips; or (iv) 12 t ha-1, alone, in 1.8-m-wide strips. All ASD-treated areas were covered with clear tarp and drip irrigated with 25 cm of water. Tarps remained for 6 weeks, during which the soil moisture level was kept at or above field capacity by drip irrigation. All trials included nontreated control and fumigated standard treatments. ASD raised temperature and reduced redox potential in soil at 15- and 46-cm depths for 6 weeks. Fumigation and ASD treatments both nearly eradicated bioassay inoculum of Pythium ultimum in the soil before almond trees were replanted and significantly affected almond tree root communities of fungi and oomycetes after planting. Fumigation treatments and ASD treatments with rice bran at 20 t ha-1 in 3.0-m strips increased tree growth significantly and by similar magnitudes. Among repeated experiments, mean increases in trunk cross-sectional area growth due to fumigation ranged from 137 to 264%, while the increases due to ASD at 20 t ha-1 in 3.0-m strips ranged from 148 to 214%, compared with controls. ASD offers effective control of PRD and is worthy of further optimization and testing for management of PRD and additional orchard replant problems.

Variability of survival and yield traits in cacao (Theobroma cacao L.) clones under marginal field conditions in Ghana

ABSTRACTIncreasing the genetic base of current parental cacao varieties grown in West Africa with clones that are able to perform well under marginal conditions could improve cacao production. Survival and yield of 30 different cocoa clones of more recent introductions were compared with five parental clones of improved cocoa varieties under natural field conditions in Ghana. A randomized complete-block design with five replications was used to evaluate the 35 clones for the following traits: percentage survival, increase in trunk cross-sectional area (TCSA), canopy spread, bean mass and bean yield. Significant (p < 0.05) clone effects for all traits and broad-sense heritability range of 0.16–0.51 were observed. Bean mass and bean yield varied from 0.90 to 1.44 g and 149 to 467 kg/ha, respectively. Bean yield and TCSA was positively and moderately correlated (r = 0.46; p < 0.01). Clones A 1/197, ICS 70 and MO 20 outperformed the best control clone for both survival and yield, which could be used in cacao breeding to improve production under marginal conditions in Ghana.

Growth Is Inversely Correlated with Yield Efficiency across Cultivars in Young Olive (Olea europaea L.) Trees

The modern olive industry is increasingly interested in olive cultivars that start producing early and remain relatively small, because they are suitable for super high-density orchards. Some cultivars are better suited to this than others but it is not clear why. Understanding the mechanisms that lead to early production and reduced canopy size is therefore important. The object of this study was to investigate whether differences in vigor across olive cultivars are related to earliness and abundance of bearing. We analyzed tree growth and productivity in young coetaneous trees of 12 olive cultivars, grown together in the same orchard. Trunk diameter increased over the observation period, reaching significantly different values across cultivars. Canopy volume also increased, reaching 2-fold differences between the minimum and the maximum values. Cumulative yield increased, reaching up to 3-fold differences. When the cumulative yield at the end of the experiment was plotted against the final trunk diameter, no correlation was found. A significant correlation was found when cumulative yield was plotted against the increment in trunk diameter during the observation period for which yield data were collected. This relationship improved (i.e., R2 rose from 0.57 to 0.83) when yield efficiency [i.e., cumulative yield per unit of final trunk cross-sectional area (TCSA) or per unit of canopy volume] was used instead of yield. These results clearly showed that trees that produced proportionally more (i.e., higher yield efficiencies) grew less. We conclude that, in young olive trees, vigor is inversely related to early bearing efficiency, which differs significantly across cultivars. The results support the hypothesis that early and abundant bearing is a major factor in explaining differences in vigor across olive cultivars.

Effects of crop load on distribution and utilization of 13C and 15N and fruit quality for dwarf apple trees

In order to define the effects of fruit crop load on the distribution and utilization of carbon and nitrogen in dwarf apple trees, we conducted three crop load levels (High-crop load, 6 fruits per trunk cross-sectional area (cm2, TCA)), Medium-crop load (4 fruits cm−2 TCA), Low-crop load (2 fruits cm−2 TCA)) in 2014 and 2015. The results indicated that the 15N derived from fertilizer (Ndff) values of fruits decreased with the reduction of crop load, but the Ndff values of annual branches, leaves and roots increased. The plant 15N-urea utilization rates on Medium and Low-crop load were 1.12–1.35 times higher than the High-crop load. With the reduction of crop load, the distribution rate of 13C and 15N in fruits was gradually reduced, but in contrast, the distribution of 13C and 15N gradually increased in annual branches, leaves and roots. Compared with High-crop load, the Medium and Low-crop load significantly improved fruit quality p < 0.05. Hence, controlling fruit load effectively regulated the distribution of carbon and nitrogen in plants, improved the nitrogen utilization rate and fruit quality. The appropriate crop load level for mature M.26 interstocks apple orchards was deemed to be 4.0 fruits cm−2 TCA.

The effect of irrigation level in the kernel dry matter accumulation period on almond yield, kernel dry weight, fruit count, and canopy size

The effect of irrigation regime in the kernel filling stage of almond was examined in a field experiment. The experiment was conducted on 9-year-old local variety (Um-El-Fahem) grafted on GF677 rootstock in Israel. Five irrigation treatments were applied during the main kernel dry matter accumulation. Irrigation rates in June varied from ~1 to ~8 mm/day and midday stem water potentials varied from ~−2.6 to ~−1.3 MPa. Seasonal irrigation varied from 394 to 801 mm. Kernel yield increased in the high irrigation treatments in the first four seasons where it decreased in the three lower irrigation treatments. Similarly, the four-season trunk cross-sectional area accumulation increased with increasing irrigation. Kernel yield increased with both midday stem water potential and irrigation rate. Kernel dry weight decreased with increasing fruit count where higher kernel weights were found in the higher irrigation treatments at similar fruit count. Kernel relative growth rates of all treatments were similar along the dry matter accumulation stage except for around 1 June where the lowest irrigation rate had significantly lower growth rate. Spurs survival analysis showed that the number of fruits per spur, fruiting spurs, and alive spurs increased with increasing irrigation.

The Influence of Rootstock on the Growth and Fructification of Cherry Cultivars in a High Density Cultivation System

The influence of rootstock on the growth and fruiting of three sweet cherry cultivars (‘Bigarreau Burlat’, ‘Kordia’, ‘Regina’) was studied under the pedoclimatic conditions of Cluj-Napoca, Romania, in 2014-2016. The trees were grafted on Gisela 5 rootstock, trained as Zahn Spindle and the orchard had a density of 1666 trees/ha. Root were cut twice, at 50 cm distance from the trunk, in an angle of 45° and 30 cm depth, as followed: first time, to the autumn, in fall leaves time, on one side of the row and the second time, in spring, at blooming time, at the other side of the row. The rootstocks influenced height of the trees, the shoot growth, the number of long and fruiting branches, trunk cross sectional area yield and precocity, with differences statistically assured. The longest shoots, in mean values, gave the variant with cultivars grafted on Mahaleb rootstock (111.7 cm). ‘Gisela 5’ rootstock decreases the average length of annual growth (93.3 cm). Trees grafted on Mahaleb formed more long fruiting branches and fewer short fruiting branches than those grafted on ‘Gisela 5’. The biggest average trunks cross sectional area were obtained for the cultivars grafted on Mahaleb (62.1 cm2). Also rootstocks influenced the height of the trees. The cumulative yield was almost double in variants where the trees were grafted on ‘Gisela 5’ (23.2kg/tree), compared to the variants where the trees were grafted on Mahaleb (13.1 kg/tree).

Comparison of Two Training Methods Applied to Apple Trees Trained to Slender Spindle During the First Years After Planting

The research was focused on the comparison of two pruning methods (winter pruning and winter + summer pruning) applied to apple trees trained to a standard and a modified slender spindle. The orchard of ‘Topaz’ trees, grafted on rootstock M 9, was planted in spring 2011. In the years 2013 – 2016, trunk cross sectional area (TCSA), crown volume, cumulative yields, yield efficiency, relative proportion of fruit size classes, number of cuts and dry matter of pruned wood were analyzed. The total growth intensity of the trees, measured by TCSA, was similar among the treatments. The trees of modified slender spindle had lower mean crown volume (2.751 – 2.765 m3) comparing to slender spindle with additional summer pruning (3.355 m3) and proved to better control the tree size. The modified slender spindle brought similar or slightly lower cumulative yields, but significantly higher proportion of good sized fruits (in categories above ř 70 mm) comparing to slender spindle. The pruning of modified spindle brings generally higher number of cuts removing a higher amount of woody biomass in comparison to slender spindle, regardless if combined with summer pruning. The additional summer pruning brought no beneficial effect in reduction of growth, fruit production and fruit size of the modified slender spindle.

Effect of tree architecture on fruit quality and yield attributes of nectarine (Prunus persica var. nectarina) cv. Fantasia under temperate condition

The present study was carried out at research farm of ICAR-Central Institute of Temperate Horticulture, Srinagar during the year 2009 to 2013. The nectarine cv. Fantasia grafted on wild peach rootstock and subsequently these trees were trained in six different training systems, viz. central leader system, open center system, Y shape- tatura trellis, four scaffolds, modified central leader system and modified open leader system. These six training systems were further evaluated for plant growth, fruit quality, and yield and average data of four years have been statistically analyzed. Significant chromatic variation was recorded for fruit skin color and maximum a* value was recorded in tatura trellis (44.13), similarly maximum trunk cross section area (TCSA) (54 cm2 ), fruit yield (32.72 tonnes/ha), fruit quality in terms of fruit weight (105.28 g), fruit length (65.53 mm), fruit diameter (66.85 mm), No. of fruits/plant (310) and yield efficiency (0.379 kg/cm2) were recorded in Y-shape tatura trellis system as compared to other traditional and contemporary tree architecture. Among biochemical parameters, highest TSS (14.66 0B) and ascorbic acid (15 mg/100g fresh fruit weight), titrable acidity (0.311%), TSS/acidity (60.89) was recorded in Y shape tatura trellis system, central leader system and modified open leader system respectively. Likewise total anthocyanin (6.23 mg cyanidin-3-glucoside equivalents 100/g fw), total carotenoids (8.71 mg/100 g), total phenols (575 mg GA equivalents/100 g), total flavonols (371 mg catechin equivalents /100 g), diphenyl-1-picryl hydrazyl (DPPH) (66 mg of AAE/100 g of fresh weight) and Ferric reducing antioxidant potential (FRAP) (69.16 mg of AAE /100 g of fresh weight) was recorded in Y shape tatura trellis followed by four scaffold training system. The present study emphasizes the superiority of Y shape tatura trellis system over other training system and could be exploited for higher quality and quantity nectarine production in temperate regions.

Responses of vegetative growth and fruit yield to winter and summer mechanical pruning in olive trees

Mechanical pruning has become increasingly common in olive orchards, particularly under high tree densities. Large cutting disks make heading cuts at a single canopy depth without discriminating between branch thickness, size, or type of branch. The objectives of this study were to: (i) quantify the responses of vegetative growth over two growing seasons and yield components over three seasons following different intensities and moments of application of mechanical pruning; and (ii) evaluate some leaf morphology and gas-exchange characteristics of the remaining leaves after pruning. Five year-old olive trees with high crop load (cv. Arbequina) were pruned towards the end of the winter (W) or early summer (S). Three intensities of winter pruning representing different distances (0.25, 0.50, 0.75m) from the outer canopy surface were applied, while there was only a single summer pruning treatment (0.75m). The vegetative growth variables measured after pruning included new branch number and length, new leaf number, and increase in trunk cross sectional area. Reproductive variables included fruit and oil yield, fruit number, fruit weight, and oil content per fruit. Growth of new branches increased significantly with winter pruning intensity while delaying pruning to early summer reduced regrowth to the level of the unpruned control. Despite differences in yield in individual years between the unpruned control and the winter pruning treatments, the average yield over the three years after the winter pruning event was similar between all trees. Delaying the intense pruning to summer was associated with some reduction in yield, and moderate winter pruning (0.50m) appeared to partially reduce alternate bearing. When measured shortly after winter pruning, specific leaf mass of the remaining leaves decreased steadily as the level of winter pruning increased, which is consistent with prior shading within the tree. The leaf net photosynthetic rate per unit mass was also different between pruning treatments. In conclusion, our results contribute to filling the gaps in knowledge related to important aspects of olive tree responses to the intensity and timing of mechanical pruning.

Effects of apple (Malus × domestica) rootstocks on scion performance and hormone concentration

New apple rootstocks that are fire blight resistant are rapidly becoming available in recent years. Rootstock effect on vigor, yield, return bloom, branch angle, bud break, and hormone profile was assessed using ‘Honeycrisp’ as the scion cultivar. Three Budagovsky (B.9, B.10 and B.7-20-20), five Geneva (G.814, G.214, G.935, G.41 and G.11) and two Malling (M.9T337 and M.26) rootstocks were used for this trial. G.814 and G.214 were high productive rootstocks, more vigorous than M.9T337 that could be interesting for weak growing cultivars such as ‘Honeycrisp’. B.9. B.10, G.41 and G.214 performed pretty similar to M.9T337, but they had slightly higher cumulative yields. High return bloom values were observed on G.935, M.9T337, and G.814, whereas B.72020 was the rootstock with the lowest values. In addition, B.72020 was the stock with more upright branches, while B.10 and G.11 had the flattest. On average, a few rootstocks had a low biennial bearing index, which included B.10 and G.814. Indole-3-acetic acid was the most abundant auxin in the xylem, being B.72020 and B.9 the stocks with higher content, while G.935 had the least. Regarding cytokinins (CK), the highest content was observed on G.11, and the lowest on G.814 and G.214. The highest ABA/CK ratio was observed on B.9, whereas B.72020 had the lowest value. On the other hand, B.72020 had the highest AUX/CK ratio value; and G.11 and G.935 the lowest. Fruit size was associated with high ABA/CK values. Trunk cross sectional area, branch angle, gas exchange variables, and biennial bearing were correlated with auxins and AUX/CK concentrations in xylem. Yield efficiency, crop load, leaf temperature, return bloom and bud break were correlated with ABA, CK, and ABA/CK in xylem. Since G.814, G.935 and G.11 had a very uniform bud break, these rootstocks could be suitable to test in areas where irregular bud break might be a problem. The high levels of endogenous ABA observed in Honeycrisp grafted on B.9 and G.11 suggests the possibility of these rootstocks tolerating drought stress by slowing evapotranspiration of the scion.

Effect of N and K Fertilizers on Growth, Yield and Quality of Pear (Pyrus pyrifolia)

The effect of different combined doses of N and K fertilizers on plant growth, fruit quality and foliar elemental composition of pear cv. Patharnakh was investigated. Experimental plants were supplied with different levels of N (460, 690 and 920 g N /plant) and K (600, 900, 1200 and 1500 g K2O/plant) in the form of Urea and Muriate of Potash (MOP) fertilizers. From the results, it was found that nitrogen application increased number of fruits/plant, trunk cross-sectional area (TCSA), shoot length and leaf N content, whereas, K application improved fruit firmness, total soluble solids (TSS), and leaf K content. Fruits harvested from T4 (460 g N:1500 g K2O /plant) treatment recorded maximum firmness. Plants under T9 (920 g N: 600 g K2O /plant) treatment showed the maximum increase in shoot length, and TCSA, whereas, T6 (690 g N : 900 g K2O /plant) resulted in maximum fruit yield. Leaf N and K concentrations improved with applications of the respective fertilizer.

Evaluation Results of Finnish Apple Rootstocks in Latvia

Abstract A trial was established in 2011 with five rootstocks - MTT1, MTT4 and control B.9 (1.5 × 4 m, five replications with two trees), MTT5 and control MM.106 (2.5 × 5 m, six replications with two trees), and two cultivars - ‘Auksis’ and ‘Gita’. The evaluated parameters were: tree general condition, flowering, and yielding intensity (points), number of root suckers, average yield (kg·tree-1), yield per trunk cross section area (g·cm-2), average fruit mass (g), and amount of non-standard fruits (%). A randomised fruit sample from each cultivar-rootstock combination was put into storage, and a panel taste was performed once each season. A snowless winter occurred in 2013/2014, when soil froze to 1.5 m depth, which was critical for MM.106. Other rootstocks did not show injury. The best results were obtained for MTT4, which was similar to that of M.26 in Finland. Its vigour was similar to MM.106, and start of bearing to B.9. Rootstock MTT5 was initially grouped with medium vigour MM.106, as having 60-80 % of vigour of ‘Antonovka’ seedlings in Finland. Yet in our trial, it had vigour and start of bearing was similar to that of B.9 or slightly larger, depending on cultivar; it has a tendency to form root suckers. MTT1, ranged with B.9 in Finland, had too weak vigour. The most promising cultivar-rootstock combination was ‘Gita’ on MTT4.